The invention pertains to methods and mechanisms to achieve three dimensional (3D) motion and fixation using pathway-based actuators. The invention has application in transportation, shipping, manufacturing, and other pursuits where it is desirable to move objects along, about and/or transverse to a pathway. By way of non-limiting example, the invention has application to achieving rotation and translation in three dimensions of objects carried by linear machines, including linear motors.
The design and manufacture of linear machines has been carried on for many years, but the applications have been primarily for motion along a single pathway or the use of two linear machines to create motion along more than one pathway. The increased use of synchronous motors is due to the evolution of microprocessors designed specifically for motor control, the availability of more cost effective power electronics, and better permanent magnets. The Linear Synchronous Motor (LSM) has benefited from advances in rotary synchronous motor technology and for many applications allows performance and cost advantages as compared with alternatives such as conveyor belts and rotary motors. There are also advantages when compared with other types of linear motors, such as the Linear Induction Motor (LIM) and the Linear Reluctance Motor (LRM).
There are several problems that linear machine designers must address: decreasing cost, reducing size and weight, increasing efficiency, eliminating cogging or ripple force, simplifying manufacturing, providing precise stopping and providing movement along more than one pathway. This patent addresses the issues of multi-pathway movement and precise stopping while retaining reduced cost, good efficiency, reduced ripple force and simplified manufacture.
Linear motors have been constructed in a manner to allow multidimensional control, but they all use two or more motor pathways to achieve multidimensional motion. Examples include: U.S. Pat. No. 3,376,578, Magnetic positioning device; U.S. Pat. No. 5,368,425, Multi-axis linear motor positioner with y-axis supported at single end; U.S. Pat. No. 5,763,966, Single plane motor system generating orthogonal movement; U.S. Pat. No. 5,938,577, Symmetrical, multi-axis linear motor machine tool; U.S. Pat. No. 6,175,169, Closed-loop planar linear motor with integral, monolithic three-degree-of-freedom ac-magnetic position/orientation sensor; U.S. Pat. No. 6,445,093, Planar motor with linear coils arrays; and U.S. Pat. No. 6,703,806, XYZ-Axes Table.
In view of the foregoing, an object of the invention is to provide improved methods and apparatus for moving people, packages, materials and other things.
A related object is to provide such methods and apparatus as are adapted for achieving rotational and translational motion of objects relative to a pathway.
A further related object is to provide such methods and apparatus as are adapted for achieving such motion using actuators that move along and/or define such a pathway.
Yet a still further related object is to provide such methods and apparatus as are adapted for use with linear motors.